New algorithm a Christmas gift to 3-D printing—and the environment

December 15, 2014
New algorithm a Christmas gift to 3D printing – and the environment
The Christmas tree in the centre was 3D-printed in the traditional manner, and displays the extra material to support each branch. Beside it are the two halves of the same tree printed using the new algorithm, with no supportive material to remove.

Just in time for Christmas, Simon Fraser University computing science professor Richard Zhang reveals how to print a 3D Christmas tree efficiently and with zero material waste, using the world's first algorithm for automatically decomposing a 3D object into what are called pyramidal parts.

A pyramidal part has a flat base with the remainder of the shape forming upwards over the base with no overhangs, much like a pyramid. A pyramidal shape is optimal for 3D printing because it incurs no material waste and saves print time.

The promises to become a big deal in the world of 3D printing, and also has applications for designing molds and for casting.

Zhang, a computer graphics expert specializing in geometric modeling and processing, developed the algorithm with PhD candidate Ruizhen Hu, an international student from Zhejiang University in China.

Their research paper, Approximate Pyramidal Shape Decomposition, was published this month in ACM Transaction on Graphics, the world's leading graphics journal. As well, Hu presented their research at a major graphics conference, SIGGRAPH Asia, this month in Shenzhen, China.

In 3D printing, the printer deposits melted plastic layer by layer in a bottom-up fashion. If the shape has an overhang, such as a tree branch, extra material has to be printed beneath it as support. This extra plastic is waste material and must be removed, which can be time consuming and difficult. And removing that supports an object's hollow interior or tiny fragile parts, like the star atop a Christmas tree, can be almost impossible without causing breakage.

"Coming up with a practical algorithm to decompose 3D objects into the smallest possible number of pyramidal parts was quite a challenge," says Zhang.

"Importantly, it is impractical for most real-world objects to be broken into exactly pyramidal parts since this would result in too many parts," he says.

SFU computer scientist Richard Zhang holds a Christmas tree, left, that was 3D-printed in the traditional manner, and the same tree, right, printed with assistance from a new algorithm he developed with PhD student Ruizhen Hu. The Christmas tree on the left has extra material between each “branch,” which is difficult and time-consuming to remove. Printing the tree on the right incurred no material waste.

"Ruizhen came up with a really clever way of transforming the problem to obtain an effective solution."

The new algorithm partitions the object into a small number of nearly pyramidal parts that can be 3D-printed with little or no material waste.

These printed parts can then be glued together to form the finished object. The Christmas tree, for example, is divided in half for fabrication, and then glued together.

New algorithm a Christmas gift to 3D printing – and the environment
Traditional method for printing a 3D Christmas tree.

In molding and casting, the ideas are similar, says Zhang. "If the molded or cast parts are pyramidal, then removing the mold or cast after fabrication would not result in any breakage," he says.

In keeping with the Christmas theme, he suggests chocolatiers could use the algorithm to design chocolate molds for Christmas trees or reindeer.

Explore further: Researcher invents 3D printing technique for making cuddly stuff

More information: The paper is available online: www.cs.sfu.ca/~haoz/papers.html

Related Stories

Does 3D printing have the right stuff?

June 23, 2014

3D-printed parts promise a revolution in the space industry, rapidly creating almost any object needed. But do the results really have the right stuff for flying in space? ESA is now checking if their surface finish comes ...

3-D printer in high demand at NSLS-II

December 11, 2014

It looks like a coffee dispenser. But the nondescript grey box tucked against a wall in Bldg. 743 is actually a 3D printer. It's in high demand by scientists and engineers building beamlines for the National Synchrotron Light ...

Recommended for you

Apple issues update after cyber weapon captured

August 26, 2016

Apple iPhone owners on Friday were urged to install a quickly released security update after a sophisticated attack on an Emirati dissident exposed vulnerabilities targeted by cyber arms dealers.

Sponge creates steam using ambient sunlight

August 22, 2016

How do you boil water? Eschewing the traditional kettle and flame, MIT engineers have invented a bubble-wrapped, sponge-like device that soaks up natural sunlight and heats water to boiling temperatures, generating steam ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.